Biopsy devices for fine needle aspiration (FNA) are widely used for screening diagnostic procedures and are useful for obtaining cytological specimens for examination, for example, to confirm the diagnosis of a suspected medical condition. Typical specimens collected include liquids or cell samples. Such devices are generally useful in sampling tissue from breast, head and neck, lymph nodes, and for some gynecologic conditions. Other applications include lung, prostate, and other soft tissue biopsies.
Generally, biopsy devices of this type extract samples of tissue through a small needle in the range of 25-18 gauge. The needle is inserted, typically through the skin, so that the tip of the needle is in the suspect tissue mass. A vacuum force is applied by withdrawing the plunger of a standard syringe attached to the needle. To aid in harvesting an adequate sample size, the needle is optionally moved in and out of the puncture site a plurality of times. This reciprocating motion causes cellular material to be scraped from the tissue and drawn into the needle. This procedure draws up a small amount of tissue fluid, together with loose cells, into the syringe, and the collected specimen can be directly placed on a slide for pathological analysis.
Most existing FNA biopsy procedures use the regular needle-syringe systems, which are designed for the purpose of injection instead of aspiration biopsy, and therefore, have many limitations. After the procedure is done with a regular needle-syringe system, the specimen usually spreads all over the needle, needle-syringe joint, and/or inside of the syringe. Only a small fraction of the collected specimen could be directly placed on a slide usable for pathological analyses, and a major portion of the specimen is left in the needle and syringe. For additional analysis, the specimen has to be transferred into different containers through an extra procedure such as washing, which would cause substantial loss of the precious specimen as well as possible damages to the fresh specimen. Often, with the existing FNA needles, the procedure has to be repeated multiple times in order to obtain enough samples for the required analyses.
On the other hand, multiple biomarker identifications have become more and more important in the modern personalized medicines, especially in cancer diagnosis and treatment. Effective uses of a small quantity of biopsy specimen for multiple tests are highly desirable and often required. Therefore, aspiration and biopsy devices and methods capable of collecting maximally usable biological samples are in great need.